الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Primary neoplasms of the small bowel are quite uncommon, representing only about (3%) of all neoplasms of the digestive tract, although the small bowel accounts for ( 90%) of the intestinal mucosal surface. Benign neoplasms account for approximately (1-2%) of all GIT tumours. Leiomyomas and adenomas are the most common types of tumours. Other types of benign tumours, such as lipomas and hamartomas, are less frequently encountered. Up to (60 - 70%) of symptomatic small bowel tumours prove to be malignant. Risk factors for the development of small bowel tumours include coeliac disease, crohn’s disease, FAP, ileal conduits, neurofibromatosis, coeliac sprue, and human immunodeficiency virus (HIV) infection. The clinical symptoms are non-specific. Most small bowel tumours are not diagnosed until complications present, such as bleeding, bowel obstruction, or perforation . Other clinical symptoms are lassitude, weight loss, abdominal pain and discomfort. Neuroendocrine tumours present with symptoms related to their hormonal activity. Most malignant small bowel tumours have already metastasized when diagnosed, which is responsible for the poor prognosis. CT has the advantage of visualizing the entire GIT as well as the extramural structures and abdominal organs. The introduction of MDCT and advanced 3D imaging capabilities have renewed interest in using CT to detect and stage small bowel tumours. The best visualization of small lesions is achieved with CT enterography (CTE) or enteroclysis. In this method, a negative enteral contrast medium (methylcellulose solution) is administered orally (in CTE), or through a nasojejunal tube (CT enteroclysis), providing distension and optimal imaging of the small bowel wall. Small bowel neoplasms often have overlapping imaging features. The differential diagnosis can be focused when typical imaging features are seen in specific locations. A polypoid or constricting annular mass in the duodenum suggests adenocarcinoma. A mesenteric mass with calcifications and speculations suggests carcinoid tumour. A large, homogeneous mass with mural thickening and lumen dilation in the ileum suggests lymphoma. Lymphoma, metastases and GISTs can cause large masses. Primary small bowel tumors are not common. Because of their non specific clinical picture, they are usually missed at diagnosis. Radiologists have a major role in the early diagnosis of small bowel tumors. MDCT provides high-resolution imaging and helps in precise localization and characterization of lesions. MPR is useful to delineate the extent of tumor and to demonstrate involvement of other organs. Attention has shifted toward MSCT to diagnose small bowel pathology. MSCT of the small bowel has sensitivity, specificity, availability and safety for being a frontline diagnostic method.